OnlyOnAOL: There's a beast inside Idris Elba

"I'm going to get a quick cut while we talk. I gotta try and stay presentable," he says, as a stylist trims his short hair.

As if he's ever anything but.

The charming, chiseled, and deeply talented British actor, who first broke out as drug lord Stringer Bell in HBO's "The Wire," has done heroic (as Nelson Mandela in "Mandela: Long Walk to Freedom") and obsessive (as cop John Luther in the series "Luther"). But now, he embodies his most brutal role yet as an unnamed commander of child soldiers in "Beasts of No Nation," directed by Cary Fukunaga.

For the father of two, being cruel to kids, and teaching them to kill, proved inexorably difficult.

"I hate seeing children suffering in film -- I hate it. It's hard to separate home from state when you've got kids and you're doing a film like that. We went away for six weeks. I didn't see my children for a long time and that's the way it had to be," he says.

His character is something of a snake oil salesman, a guy who leads his followers through a combination of bullying and black magic.

"Snake oil salesman, that's an interesting phrase," says Elba. "This is a man who didn't intend to be who he is, but is now so caught off from himself and is a hero to those soldiers. He got seduced into that power. He's like a pied piper for the kids. That's an interesting dynamic to play."

The film has a 91 percent rating on Rotten Tomatoes, and is available on Netflix. But because he's shooting "Star Trek Beyond," Elba hasn't been on the promotional circuit much, something he's thankful for. The process of wooing Oscar voters is "weird," he says.

"You have to go work this party. Why? Because the voters are there. I hate that. It's great that I'm working and I don't have to. It feels a little bit, gluttonous if you like, to ask people to consider you for an award. The award is the fact that this film was made," says Elba.

Professionally, he likes to shake things up.

"I make commercial films. I make television that is entertaining. I wanted to make something that hits you hard, that's more challenging for the audience. This is a character I would like to breathe life into. He's despicable, there's no doubt about it," he says.

Elba's got a legion of fans, including Mark Consuelos, who told us he once screamed his name out of a car window.